JPS63234657A - Signal transmission system - Google Patents

Abstract

PURPOSE:To ensure crosstalk attenuation even through an unbalanced signal transmission line by providing an inverting means inverting the phase of input/ output on the optional position of the signal transmission line. CONSTITUTION:Induction currents (b), (c) are generated in a channel 31 by a signal current (a) flowing to a speech path 30. Since a phase inverting transformer 40 is provided on the speech path 31, the induced currents (b), (c) are cancelled and the effect of the channel 30 in the channel 31 is reduced. Moreover, the direction of winding of the phase inverting transformer 40 is made opposite and the transformer 40 is provided at a position by which the induction current (b) is nearly equal to the current (c). Thus, the crosstalk attenuation is ensured even through the unbalanced type signal transmission line and small- sized and low cost device is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a signal transmission method performed via an unbalanced signal transmission path.

(Prior Art) Conventionally, in electronic key telephone devices, etc., a group of cross-point switches is generally provided for switching communication paths within the main device, and any crossing point of this group of cross-point switches is closed/connected. This forms a communication path between the corresponding telephone line and the key telephone. It is well known that a C-MOS type semiconductor switch matrix is used as this type of cross-point switch group.

By the way, in electronic key telephone devices that use such semiconductor switch matrices, one side of the communication path is connected to a common potential (
(ground connection) to form an unbalanced signal transmission path and perform exchange connections. A group of so-called unbalanced crosspoint switches is often used. In particular, it is often used in small-scale electronic key telephone devices, such as 6-station, 16-extension terminals.

Next, the configuration of the electronic key telephone device having an unbalanced signal transmission path shown in FIG. 7 will be briefly described. Signals from the office line are guided to the office line interface circuit 10 in the main device 1, where they are separated into the office line current (direct current) and the audio signal. Then, the separated office line current flows through the DC circuit 10A in the office line interface circuit 10 and is fed back to the office line side. On the other hand, the voice signal is guided to the crosspoint switch 11 via the transformer IOB, and after the exchange and connection operation here, the voice signal is transferred to the transformer 3, the voice transmission line 1+, the transformer 21 of the button telephone 2, the sidetone prevention circuit 22, and so on. transformer 2
1, audio transmission line 1t, ) lance 3, cross point switch 11. ) is transmitted to the central office line via the lance 10B. In addition, the control unit 4 of the main device 1 and the key telephone 20
The controller 27 is connected to the parallel/serial converter 5, transformer 6, data transmission line 12, transformer 25, and parallel/serial converter 26, and exchanges control data with each other. Further, the control section 4 controls various operations of the main device 1, and the control section 27 controls various operations of the key telephone 2.

In this case, power to the button telephone 2 is supplied from a power supply 12 in the main device 1 via transformers 3 and 6.

However, when a device with such an unbalanced signal transmission path is suitable for a large-capacity device with an increased number of office lines and extension terminals, the wiring pattern for connecting each crosspoint switch becomes long. However, a problem arises in that the induced components generated between the wiring patterns increase. In other words, when the induced component increases, the amount of crosstalk attenuation deteriorates, resulting in the inconvenience that crosstalk occurs.

Such an induced component occurs due to the length of the wiring pattern and the distance between the wiring patterns.

By the way, as a countermeasure against such an inductive component, a method of overlapping may be considered, but this method requires twice as many cross-point switches, which is disadvantageous in that it is not suitable for downsizing and lowering the cost of the device. Note that FIGS. 8 and 9 show unbalanced and balanced signal transmission paths, and the X marks indicate crosspoint switches.

[Problem that the invention seeks to solve]

As mentioned above, in the device having the unbalanced signal transmission path, as the signal transmission path becomes longer, there is a problem in that crosstalk occurs due to mutually induced components between the two. . Therefore, the present invention aims to eliminate this problem and provide a signal transmission method that can ensure crosstalk attenuation even with an unbalanced signal transmission path and is also suitable for downsizing and lowering the cost of equipment. purpose.

[Structure of the invention]

(Means for Solving the Problems) 4. The present invention achieves the above object by providing a reversing means such as a transformer for reversing the phase of the human life output at any position of the unbalanced signal transmission path. did.

(Function) In the present invention, the reversing means can cancel the induced current generated on the same signal transmission path, so that the amount of crosstalk attenuation in the unbalanced signal transmission path can be ensured.

(Embodiment) FIG. 1 shows an embodiment of a communication path to which the present invention is applied, and FIG. 2 is a conceptual diagram thereof. Note that this embodiment is applied to the button telephone device shown in FIG.

In these figures, the X marks indicate crosspoint switches;
FIGS. 1 and 2 show a state in which a communication path is formed between the office line interface circuit and the key telephone set or between the key telephone sets by closing the switch.

The return sides of the communication paths 30 and 31 are kept at a common potential (grounded), and these communication paths 30 and 31 constitute an unbalanced communication path. Now, due to the signal current a flowing through the communication path 30, induced currents S and C are generated in the communication path 31. However, since the phase inversion transformer 40 is provided in the communication path 31, these induced currents S and C are canceled out.
The influence of the communication path 30 on the communication path 31 is reduced. Incidentally, the connection in the winding direction of the phase inverting transformer 400 is reversely connected, and the transformer 40 is provided at a position such that the induced current b÷C. In addition, actually 3oc11
The improvement rate is 10 to 15 d when a balanced pattern of about 1 m is wired on the board to form an unbalanced communication path.
It was B.

3 and 4 are schematic configuration diagrams showing other embodiments of communication paths to which the present invention is applied. According to the embodiment shown in FIG. A phase inversion transformer 40 is provided at 31 and 33. Further, according to the embodiment shown in FIG. 4, a plurality of phase inverting transformers are provided in the communication path 34 to further reduce mutual interference. FIG. 5 is a schematic configuration diagram showing still another embodiment of the communication path to which the present invention is applied, and according to this embodiment, the position of the phase inverting transformer 40 provided in each communication path on the mother board 110. are divided into odd-numbered communication paths (CHI, 3...) and even-numbered communication paths (CHI, 3...).
2, 4,...) to further reduce mutual interference. In addition, 101 to 10n indicate printed wiring boards on which button telephone interface circuits are mounted,
Three interface circuits are mounted on each printed wiring board 101 to 10n. Moreover, each printed wiring board 101~
10n is connected to a motherboard 110 (backboard) via a connector, and a communication path (CHI
~CHn) is provided as a wiring pattern. 11
1 to lln are semiconductor crosspoint switches. FIG. 6 shows the structure of this embodiment, in which a printed wiring board 200 on which an interface circuit is mounted is mechanically and electrically connected via a connector 60. If the phase inverting transformer 40 is provided on the mother board 110 where the communication path is wired in this way, there is no need to change the other boards 101 to 10n1200, and the communication path and control signal path can simply be formed. It is only necessary to change the motherboard 110, which is the motherboard 110, from the conventional one, which is advantageous in terms of manufacturing and wiring checking.

〔Effect of the invention〕

As described above, according to the present invention, crosstalk attenuation can be ensured even in an unbalanced signal transmission line, and the present invention is also suitable for downsizing and lowering the cost of the device.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
A conceptual diagram of the embodiment shown in the figures, FIG. 3 is a block diagram showing another embodiment of the present invention, FIG. 4 is a block diagram showing still another embodiment of the present invention, and FIG. 5 is a block diagram showing another embodiment of the present invention. Furthermore, FIG. 6 is a diagram showing the structure of the embodiment shown in FIG. 5, FIG. 7 is a block diagram of a conventional key telephone device, and FIG. 8 is an unbalanced telephone call diagram. FIG. 9 is an equalization circuit diagram of a balanced communication path. 1... Main device 2... Key telephone 30.31,
32, 33...Communication path 40...Phase inversion transformer 111~lln...Semiconductor cross point switch Patent attorney Noriyuki Ken Yudo Sanno -

Claims (5)

[Claims] (1) In a signal transmission method that is carried out via an unbalanced signal transmission path configured so that the return side of the signal transmission path has a common potential, input and output phases can be set at any position on the signal transmission path. A signal transmission method characterized by being provided with a reversing means for reversing the . (2) A plurality of the signal transmission paths exist adjacent to each other, and the reversing means is provided at a different position with respect to the adjacent signal transmission paths.
Signal transmission method described in section 1). (3) Signal transmission according to claim (1), wherein a plurality of the signal transmission paths exist adjacent to each other, and the reversing means is provided for every other signal transmission path. method. (4) Claims (1) to (3) characterized in that a group of exchange switches is connected to the signal transmission path.
The signal transmission method described in any of paragraphs. (5) The signal transmission system according to any one of claims (1) to (4), wherein the reversing means is a phase reversing transformer.